# Inductance of a torus

Problem by zainul abidin
30 Nov 1999 00:00 WIB

Determine the self inductance of a torus with major radius R and minor radius r,  which is tightly wound with N turns of wire. Assume that $R>>r$ and that the magnetic field within the region of the torus cross-sectional area, $A=\pi r^2$, is essentially of a long solenoid that has been bent into a large circle R.